The term "biological drugs" (or biological agents, or biologics) is usually applied to denote a class of medicinal products (either already approved to trading or in clinical trial stages), manufactured by means of biological processes, involving recombinant DNA technology. These medications are divided into three types - key signalling proteins (e.g. erythropoietin), monoclonal antibodies and receptor constructors. It has been shown in many clinical studies that biologics offer additional therapeutic options, which are effective for treatment of many diseases in the fields of rheumatology, oncology, dermatology, pneumonology and others. However, the access to these medicines is different in various European countries and depends on many aspects, including adverse episodes, complex regulatory standards and pharmacoeconomic aspects. Selected problems of access to biologics for therapeutic purposes are discussed in this article, both in Polish and European perspective. Seemed to be safe biological agents (named biologicals too) can produce unwanted, adverse side-effects. The side-effects in the course of treatment with biologicals may result from excessively secreted cytokines during treatment, hypersensitivity reactions, cytokine balance disturbances, cross reactions or nonimmunological reactions. Clinically, the first type is usually manifested by influenza-like symptoms. Hypersensitivity reactions depend on the degree of antibody humanisation, the applied adjuvant and, what is important, these are often delayed immunological reactions, mediated by T lymphocytes. Autoimmune reactions are a serious threat for affected patients. The syndrome of disturbed cytokine balance may, however, manifest itself by the occurrence of tuberculosis, listeriosis or granulomatosis, while such complications have also been observed in patients treated with anti-TNF alpha. Non immunologically determined symptoms, such as circulatory failure or hearing loss, may be dangerous as well.(original abstract)